This invention relates to a quick coupler, and more particularly to a quick coupler for attaching an implement to, and detaching an implement from a vehicle equipped with a lift arm and a tilt link.
An earthmoving vehicle equipped with a lift arm and a tilt link, such as a wheel loader, may accomplish a multitude of operations by attaching various working implements thereto. For instance, a loader equipped with a bucket can load and transport earth or the like, while a loader equipped with a fork can load and transport material on pallets or pipes. In this manner a single earthmoving vehicle may be used for multiple purposes, if such implements may be conveniently attached to the vehicle as required.
Quick disconnect and attachment mechanisms for securing various implements to a vehicle are exemplified by U.S. Pat. Nos. 3,243,066, issued Mar. 29, 1966 to C. W. Gardner, et al; 3,417,886, issued Dec. 24, 1968 to C. F. Stuart; 3,760,883, issued Sept. 25, 1973 to B. D. Birk; 3,818,551, issued June 25, 1974 to S. J. Coughran, Jr.; and 3,935,953, issued Feb. 3, 1976 to R. N. Stedman.
However, the known prior art mechanisms, including those designated immediately above, are unsatisfactory from several standpoints. For example, the relatively complex mechanism of U.S. Pat. No. 3,760,883 is subject to misalignment problems so that the powerably moved pins on the hitch have difficulty extending into the openings provided therefor on the implement. Moreover, such pins are exposed to dirt and tend to wear unevenly, causing undesirable looseness in the coupling. Other known mechanisms are excessibly large or are of a construction which subjects the hydraulic jack thereof to impart loads during operation of the implement. Still further, some mechanisms are subject to possible disengagement problems as a result of inadvertent leakage of the fluid communicating with the hydraulic jack, and which jack provides for quickly disconnecting the hitch portion carried by the vehicle from the hook portion secured to the various implements.